1. Field of the Invention
The present invention relates to a composition usable for preventing or treating Salmonella Typhimurium infection comprising a bacteriophage, isolated from nature and capable of infecting Salmonella Typhimurium so as to kill the same as an active ingredient, and a method for preventing and treating Salmonella Typhimurium infection by using the said composition. More precisely, the present invention relates to a bacteriophage isolated from nature which is characterized by having the genome represented by SEQ. ID. NO: 1 and is capable of killing Salmonella Typhimurium specifically, a composition usable for preventing and treating Salmonella Typhimurium infection comprising the said bacteriophage as an active ingredient, and a method for preventing and treating Salmonella Typhimurium infection by using the said composition.
2. Description of the Related Art
Salmonella is similar to E. coli in the aspects of morphology or physiology but is categorized in an independent genus for the convenience in clinical use by the proposal of K. Kauffmann et al. Salmonella has been isolated from enteritis and gastroenteritis patients and from animals with diverse diseases since Salmonella Choleraesuis was first isolated from a pig died of hog cholera by Salmon and Smith in 1885. Salmonella has also been isolated from healthy animals such as chicken, cow, pig, goat, dog, and cat and from our environment.
More than 2,000 serotypes of Salmonella have been reported so far and it can be largely divided into two groups, one of which is the group that has host specificity and the other of which is the group that does not have host specificity. Salmonella is Gram-negative bacilli and spore is not formed. It is a parasite living in a variety of animals.
Salmonella infection is generally called salmonellosis, which carries the symptoms of rough skin, anorexia, conjunctivitis, depression, loose feces, splenomegaly, and even death.
The most frequently found Salmonella in pig industry is Salmonella Typhimurium. The loss and damage caused by Salmonella Typhimurium infection in livestock industry, particularly in pig industry, is huge. Therefore, it is urgently requested to develop a novel method to prevent and treat Salmonella infection efficiently.
The utilization of bacteriophage is now highly drawing our attention as an effective way of treating bacterial disease. In particular, our interests in bacteriophage grow with the preference of nature-friendly method. Bacteriophage is an extremely small microorganism infecting bacteria, which is generally called phage in short. Bacteriophage replicates within bacteria after infection. Upon completion of the multiplication, offspring bacteriophages are coming out of the host cells with destroying the host bacteria. The infection of bacteriophage in bacteria is very unique and specific, so only specific bacteria can be infected with a specific bacteriophage. That is, there is a limitation in bacteria that can be infected with bacteriophage. Thus, bacteriophage can only kill specific target bacteria without affecting any other bacteria.
Bacteriophage was first found in 1915 when English bacteriologist Twort was studying on the phenomenon that micrococcus colony was being melted clearly by some reasons. And also, French bacteriologist d'Herelle noticed that Shigella disentriae was melted by something in filtrate of dysentery patient's feces and afterwards he discovered bacteriophage independently by the following study and named it bacteriophage which meant ‘eating bacteria’. Since then, bacteriophages corresponding to different pathogenic bacteria including Shigella, Salmonella and Vibrio cholerae have been continuously reported.
Owing to its capability of killing bacteria, bacteriophage has been in the center of our interest to fight with bacterial infection and studies followed thereon. However, since Flemming found out penicillin, antibiotics have been supplied and the study on bacteriophage has been limited in some east European countries and old Soviet Union. It was not until 2000 that the conventional antibiotics demonstrated their problems in use because of increasing antibiotic-resistant bacteria. So, once again, bacteriophage draws out attention as an alternative anti-bacterial agent that can take the place of the conventional antibiotics.
The present inventors have tried to develop a composition usable for preventing or treating Salmonella Typhimurium infection by using a bacteriophage isolated from nature and capable of killing Salmonella Typhimurium selectively and tried further to establish a method to prevent or treat Salmonella Typhimurium infection by using the said composition. As a result, the present inventors succeeded in isolation of a proper bacteriophage from nature and obtainment of a sequence of the genome distinguishing the phage from others, leading to the completion of the present invention by confirming that the composition developed by the inventors could be effectively used for the prevention and treatment of Salmonella Typhimurium infection.